Thanks Vince,

Yeah, there was “quite a bit” of bleeding. Heck, I cut thru cortical and into medullary bone. Pulsed Nd:YAGs have the intensity at depth to cause a deeper zone of “injury” that is reversible, not necrosed.

Sorry, I don’t know what her INR (International Normalized Ratio) levels are at. Low = 1.5 (too thick); OK = 2.0 – 2.5; High > 4.0 (too thin).

It has never mattered in 12 years of using pulsed Nd:YAG lasers how high their INR levels are. I have NEVER had to take a patient of Coumadin (or any anti-coag tx) for ANY kind of surgery or extraction.

That’s the challenge we face as clinicians. Sometimes these paients fall into our chairs in pain and in need for treatment. Technology can help us treat them in FAR less riskier ways.

I have literally had men CRY when I told them I did not need them to be off their Coumadin AT ALL, let alone for for 3-4 days for their Laser Perio or extraction or whayever…….yet, I’ve never had a physician contact me and inquire about it, other than to tell the patient, “Oh, that’s great!”

The same goes for hemopheliacs we have treated–unlike one patient who we know died at a local university after a “simple” extraction. This is a California university who’s dean has repeatedly refused our overtures to introduce lasers into their school……. before and after the 18 year old died.

A shameful abdication of their public trust……

Bob

Al–

Ha!  That’s funny.  Or maybe “length lengthening”?

“Can the Nd:YAG not be physically used to ablate osseous structure OR would the power settings needed to cut bone cause necrosis?”

That’s a really good question.  The short answer is yes, it can.  But does any Nd:YAG device have the “right” parameters to do it safely, AND is it the best instrument for the job when we have other, and arguably “better” and safer instruments and devices?

If you use a short enough pulse duration with ANY laser–including a pulsed Nd:YAG–you can cut just about ANYTHING with absolutely NO thermal necrosis.  For example, a femto-second pulsed Nd:YAG (quadrillionths of a second PD) is used to ablate the explosive detonators in nuclear weapons (to dismantle them) because it has absolutely no thermal or mechanical effects on the explosive substrate.

http://www.llnl.gov/str/Stuart.html

The question Del and I have not investigated enough is whether or not 100 usec is short enough to safely remove bone.  (We’ve sort of been focused on regenerating bone).;)

I mean, you have seen how we have used it to remove decay and healthy dentin at 100usec–no problem.  Why not bone?  My answer has been, “if it isn’t cheaper, faster, better (using a laser), why do it?”  I haven’t found (ore even looked at) an answer to that for bone removal with Fr Nd:YAG.  

ALSO, companies that recommended bone removal in the past with pulsed Nd:YAG lasers had lasers with LONG pulse durations (800 usec & 50 Hz fixed settings) and said it was safe as long as “air and water” was used.  WRONG!!  After many patients were severely hurt, and many dentists sued for malpractice using this pulsed Nd:YAG configuration (albeit super long PD), the interest in it was understandably diminished!

“At 4.0 W you have to really know what you are doing with an Nd:YAG, right?”

Well, yes and no.  That statement applies to ANY laser, I think.  But pulsed Nd:YAG are much more “forgiving” to the tissue and the operator than a CW diode, for example.  By that I mean, at 100 usec “on” time the “off” time is 49,900 usec.  That’s almost a 500 x thermal relaxation time between pulses to the tissue.  Therefore, your average power MUST be higher than a CW laser to work at a reasonable rate of speed.

At 4.00 watts, I will drag that across my finger w/o any injury.  I wouldn’t do that with a diode or argon at 1.00 watt w/o a burn.:o

Also, since I was using a 400 micron diameter fiber, my energy density (spot size is bigger) is less concentrated, so I actually need a higher setting of Average Power to make up for the reduced energy density at the tip.

So, using a pulsed Nd:YAG is a lot easier that you might think–especially when you can vary the parameters as much as we can with the…..(you know)……PerioLase MVP-7.  😉

WARNING:  I have a financial interest in the PerioLase as co-founder of the company that manufactures it.

Bob